Astronomers find twin Earths

Earth has a few more near-twin planets outside our solar system, tantalising possibilities in the search for extraterrestrial life.

Astronomers announced yesterday that depending on definitions, they have confirmed three or four more planets that are about the same size as Earth and are in the not-too-hot, not-too-cold 'Goldilocks Zone' for liquid water to form.

These planets are likely to be rocky like Earth, and not gas giants or ice worlds. They get about the same heat from their star as we get from the sun.

That brings the total number of planets that are no bigger than twice Earth's size and in the habitable temperature zone to eight or nine.

NASA also announced that its planet-hunter telescope confirmed its 1,000th planet outside the solar system, most unlike Earth.